Your assessment of of antivirus programs as "searchers and
destroyers" is overly optimistic. Virus scanners are quite
good at identifying and disabling viruses. They are only
moderately good at repairing the damage that's been done.
The reason is simple: In order to repair the damage they
would have to ***know*** what was there before. They
would require an intimate knowledge of all files and of the
whole registry, which they don't have.
It's like a doctor: When you break a leg then the doctor
can put it in plaster. He cannot heal it - the body must heal it
by itself. Unfortunately Windows has no self-healing capacity.
If a file is damaged then it remains damaged. If a registry
entry is incorrect then it usually remains incorrect.
Having said this, you can scan your PC from here:
www.antivirus.com ("free online scan"). You can also
install Trend Internet Security, or any of the other virus
scanners. Whether it will fix your problem remains to be
seen. I would have given up a long time ago in the recognition
that the machine is now compromised and needs to be
reloaded.